One thing I've noticed using the Nomad that I don't know if it has been mentioned or not...... People in cars tend to give you more room. They seem to think you have a child in the trailer so they seem to give you more room when passing. This fact alone made touring with the Nomad my preferred choice. As for one wheel being off the road..... Never been a problem since I don't ride that close to the shoulder. I tend to make drivers drive around me instead of trying to squeeze through. Less stress seems to be applied to the rear of the bike with a two wheeled trailer as well.
Keep in mind I'm not a fan boy. I don't like touring with either...... I prefer panniers but.. If I had to choose hooking up a trailer to my Carbon road bike it would be a Burley Nomad. My same thinking would go for an alum Cannondale.